Just how bad tonight?

The last thing meteorologists need to do is warn people about severe weather -- only to have none develop. There already are enough skeptics out there.

But forecasters seem to be taking a bullish approach about the predictions overnight in the Charlotte area.

Typically, thunderstorms weaken at night, because one key ingredient -- the unstable atmosphere caused by daytime heating -- disappears. Occasionally, however, a weather system brings along its own trouble, and some meteorologists think that will be the case tonight.

A few strong storms developed Wednesday afternoon across the Carolinas, but they're not related to the system expected early Thursday morning.

Jeff Taylor, of the National Weather Service office in Greer, S.C., said late this morning that the atmosphere will have plenty of shear -- winds blowing from different directions at various altitudes. Helicity, or the spinning motion in the atmosphere, also could be significant. Thunderstorms that move into such conditions often turn severe.

Forecasters are strongly convinced that a major tornado outbreak will take place this afternoon and evening in northern Alabama, southern Tennessee and northwest Georgia. They think that same system will convert from a broken line of storms -- a condition in which tornadoes form more easily -- to a solid line as it moves into the Carolinas overnight.

Solid lines of storms don't produce many tornadoes, but they are very capable of the kind of damage we saw early April 5, when strong winds knocked out power to more than 300,000 customers in the region.

So pay attention to forecasts tonight.